Vaulted ceilings exist. Even in new construction there really isn't a universal answer for this. Different localities have different codes and norms.

Mine has a loft conversion, with a proper floor. The insulation sits between the roof and the ceiling. So...no.

My house has been a bit of an adventure for wiring.

• family room addition, post and beam with vaulted ceiling. Walls an ceiling filled with foam, no gaps
• exterior walls plaster and lathe over block, no gaps, depth for only the smallest electrical boxes.
• basement and ceiling are open, phew.

I’ve made good use of those flexible drill bits to grab wire up from the basement or down from the attic, but the family room has no access.

An example workaround is the family room air conditioner. There’s no place to rum vents back to the central hvac so it’s a mini split. The wiring goes from basement, along the chimney up to the attic, across the attic to the far end of the house and out through the wall, then run externally to the compressor

First floor in a two story house in an area with a high water table, resulting in not crawl space or basement.